LinksGadget.ascx

ASP.NET user control Reference

An .ascx file is a user control for ASP.NET Web Forms. The file contains a reusable page fragment with markup and server controls. Pages embed the control, and the server renders it as part of the page. The web server refuses direct requests for .ascx files. The code-behind file carries the control logic.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.